SI8605 Datasheet, PDF (20/40 Pages) Silicon Laboratories – BIDIRECTIONAL IC ISOLATORS WITH UNIDIRECTIONAL DIGITAL CHANNELS

Si860x
4. Device Operation
Device behavior during start-up, normal operation, and shutdown is shown in Figure 16, where UVLO+ and UVLO-
are the positive-going and negative-going thresholds respectively. Refer to Table 14 to determine outputs when
power supply (VDD) is not present.
4.1. Device Startup
Outputs are held low during powerup until VDD is above the UVLO threshold for time period tSTART. Following
this, the outputs follow the states of inputs.
4.2. Undervoltage Lockout
Undervoltage Lockout (UVLO) is provided to prevent erroneous operation during device startup and shutdown or
when VDD is below its specified operating circuits range. Both Side A and Side B each have their own
undervoltage lockout monitors. Each side can enter or exit UVLO independently. For example, Side A
unconditionally enters UVLO when AVDD falls below AVDD_UVLO– and exits UVLO when AVDD rises above
AVDD_UVLO+. Side B operates the same as Side A with respect to its BVDD supply.
UVLO+
UVLO-
AVDD
UVLO+
UVLO-
BVDD
INPUT
tSTART
OUTPUT
tSD
tSTART
tSTART
tPHL tPLH
Figure 16. Device Behavior during Normal Operation
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Rev. 1.4